GASTRIC JUICE, AN$ STOMACH DIGESTION". 133 



is accomplished. It is triturated and disintegrated by the teeth, 

 and, at the same time, by the movements of the jaws, tongue, and 

 cheeks, it is intimately mixed with the salivary fluids, until the 

 whole is reduced to a soft, pasty mass, of the same consistency 

 throughout. It is then carried backward by the semi-involuntary 

 movements of the tongue into the pharynx, and conducted by the 

 muscular contractions of the oesophagus into the stomach. 



GASTRIC JUICE, AND STOMACH DIGESTION. The mucous mem- 

 brane of the stomach is distinguished by its great vascularity 

 and the abundant glandular apparatus with which it is provided. 

 Its entire thickness is occupied by certain glandular organs, the 

 gastric tubules or follicles, which are so closely set as to leave 

 almost no space between them except what is required for the 

 capillary bloodvessels. The free surface of the gastric mucous 

 membrane is not smooth, but is raised in minute ridges and pro- 

 jecting eminences. In the cardiac portion (Fig. 25), these ridges 

 are reticulated with each other, so as to include between them 

 polygonal interspaces, each of which is encircled by a capillary 

 network. In the pyloric portion (Fig. 26), the eminences are more 



Fig. 25. 



Fig. 26. 



Fig. 25. Free surface of GASTRIC Mucous MEMBRA XK, viewed from above ; from Pig's Sto- 

 mach, Cardiac portion. Magnified 70 diameters. 



Fig. 26. Free surface of GASTRIC Mucous MEMBRANE, viewed in vertical section; from 

 Pig's Stomach, Pyloric portion. Magnified 420 diameters. 



or less pointed and conical in form, and generally flattened from 

 side to side. They contain each a capillary bloodvessel, which re- 



